Convertible roof elements for shading squares and inner courtyards have the advantage over static structures that when shading is no longer required, e.g. during the evening hours, the element providing the shade can be moved and the warm air underneath it can escape upwards. Furthermore, all the areas no longer covered with a roof are able to radiate energy into the cold night sky. This enables the square shaded during the day to cool down over night.
In case of the roof structure known from http://www.sl-rasch.de/ (“Convertible Roof for the Quba Mosque, Medina, Kingdom of Saudi Arabia”), parallel running guide ropes are stretched over the inner courtyard of a building and are braced on opposing sides of the building surrounding the inner courtyard. Along the guide ropes are displaceably arranged two membranes, which can be slid into a parking position on either building wall, where they are stored in a collapsed condition.
The disadvantage of this roof structure is that the guide ropes may impair the aesthetic impression of the building when the roof is open (membrane in parking position). Moreover, there is a risk that the square underneath it may be soiled by bird droppings.
The object of the invention is therefore to propose a convertible roof element and a roof structure that enable flexible shading of the inner courtyard and avoiding the disadvantages mentioned above.